Start-stop telegraph



R. G. GRIFFITH March 8, 1938.

START-STOP TELEGRAPH Original Filed May 29, 1935 -2 Sheets-Sheet 1 NQFIM March/8, 1938- R. e. GRIFFITH I ,1 ,5

START- STOP TELEGRAPH Original Filed May 29, 1955 2 Sheets-Sheet 2 197' 7' OIP/VE VS v Patented Mar. 8, 1938 smres ATENT orrms START- STOP TELEGRAPH Ronald George Griffith, Upper Warlingham, England Original application May 29, 1935, Serial No. 24,153, new Patent No. 2,075,712, dated March 30, 1937. Divided and this application January 20, 1936, Serial No. 59,948. In Great Britain November 12, 1934 8 Claims. (Cl. 1'78-53.1)

This invention relates to start-stop telegraph be transmitted. The invention may be applied systems and comprises matter divided from applito various kinds of start-stop transmitters, such cation for Letters Patent No. 2,075,712, March 30, as keyboard controlled apparatus, tape controlled 1937; it is particularly concerned with the transapparatus and so forth. The operation of the 5 mitting mechanism of start-stop printing teletransmitter in any event controls the successive 5 graphs employing an equal length code. In such axial positions of the cam shaft and the latter systems, the transmission of each character inmay then be provided with a cam so that at volves the sending of a starting impulse, a numeach revolution of the shaft corresponding to her of permuted code impulses followed by a ne i pu e f a Character signal, the

stop impulse. pending upon the axial position of its shaft, 10

The object of the invention is to provide a p r s o m v a c c -m k n m mber mechanism of simple construction in which, in n One d ec o e ether for effective a the transmitting mechanism, a minimum disto-rmission of the two forms of impulse constituting tion of the transmitted signals shall be produced the ompl t s s representing sm t d with a given amount of manufacturing irregu- Character S 15 larities. Then a greater part of the margin of In Order that the invention y be clearly signal distortion provided for in the receiving understood and readily carried into effect, it will apparatus may be utilized to allow for the disbe more fully explained by way of example in tortion produced in the connecting media, that its app i a to a keyboard controlled t g is to say, a telegraph line or the radio 11111;, telegraph transmitter, with reference to the ac- 20 According to the present invention, a rotating e p y drawings, in Whiehi member, such as a cam shaft, is provided for Figure 1 i a side elevation Of the s nt al the transmitter and is arranged to form or to Pa Of the transmitter; and control a signal member arranged to select each Figure 2 is a perspective View of e main Darts 5 transmitted impulse mechanically, and that ro- 0f h transmittertating member is driven at such an angular veloc- Referring to the drawings, e selecting Ca ity that it executes one revolution in a time equal shaft is shown at l and the five selecting s to one or more signal impulse periods but not at 2", and F with the start 0am at exceeding the time of all the code impulses of The shaft is driven through e friction e one complete character signal. It is preferred Capable of pp from a shaft Constantly for the rotating member or cam shaft t b driven at a suitable speed, but when a character driven so as to complete one revolution or a half i transmitted y the depression of y ey,

revolution in the time required for transmitting mechanism is ar n ed to Wit draw the usual each permuted code impulse. Thus, a selecting detent 3 from a stop surface .t carried by the cam shaft is provided, arranged when released shaft I, so that the latter is frictionally driven to make a predetermined amount of angular mot 'O h One Complete revolution. whereupon the tion, usually one complete revolution or a half detent holds it up again. Thus, the shaft i makes revolution. The selecting cam shaft is associone complete revolution for each character transated with means for operating different selecting mitted. Actually, before the five code cams 0 devices provided for dealing with successive im- 2 2 come into operation, the additional 40 pulses at regular intervals in its rotation and the start cam 2 first of all sends a starting impulse transmitting cam shaft is geared to the selecting and when the five cams 2 2 have operated,

cam shaft with such a ratio that the transmita stopping impulse may be sent. ting shaft rotates more quickly than, the select- One of the key levers is indicated at 4 and 4,5 ing cam shaft, and preferably so that it makes each has an extension 5 engaging a notch 6 in one revolution during each angular movement of a lower extension of the corresponding selector the selecting cam shaft equivalent to one signal frame 1. There are consequently a number of impulse. In other words, one revolution or a half selector frames 1 equal to the number of characrevolution of the transmitting cam shaft is equal ters provided on the keyboard. When a key is to an exact multiple of the impulse submultiples depressed, the extension 5 draws down the cor- 5 of the selecting cam shaft. responding selector frame 1 against the action The cam shaft may be mounted so as to be of a tension spring 8 and, as a result, certain capable of motion in the direction of its axis internal projections 9 on the frame I operate and capable of taking up one of two positions upon a series of vanes l0 carried on spindles l l, corresponding to the two kinds of impulses to the frame 1 at this time being guided on fixed 55 against the tension of the spring H32.

pins l2. The number of the vanes It] provided depends on the number of code elements used. In the case illustrated five are provided. As a result, according to the particular combination set by the key which has been depressed, certain of the five vanes H] are turned clockwise and certain of them counter-clockwise.

Spaced from the frames i along the spindles N, there are further five frames 98 98 98, 93 and 98 each of which has one projection corresponding to those shown at 9 in position to be engaged by one of the vanes lli. Thus, these additional frames 98 98 each correspond to one of the five vanes l and by means of the vanes each will be caused to take up an upper or lower position at each selection on the depression of one of the keys 4. These five additional frames have projections to the rear, shown at E3, M, which are moved to the upper or lower position with the frame in question.

A cam shaft [5, bearing an eccentric cam 55, is also released and actuates a lever ll pivoted at IS. The lever ll has a pair of horns I3, 23 co-operating with the cam 56, the former providing for positive forward motion of the lever I 1 and the latter for positive return motion. Thus, at each selection the lever ii is moved forward and five further levers Zi 2W, each carried on a pin 11 projecting from the upper end of the lever H, are thrust forward and are caused to co-operate with the projections i3, M of the corresponding permutation frame 38 98 Each lever 21 H has a transverse bar 22 and two forward projections 23, 23. The purpose of the transverse bar 22 is to engage with a pointed projection 25 on each of the permutation frames so that if it chances that any one of the permutation frames has not been quite fully moved to the upper or lower position, the bar 22 engages above or belowthe corresponding projection 25 and positively thrusts the permutation frame into its full upper or lower position. If a permutation frame is .in the full upper position then the corresponding projection 24 abuts against the projection I 4 of the corresponding frame so that the lever 2! is rocked upwards into the position seen at 2 l in Figure 1. If, previously, it were in the positionshown at 2| in Figure 1, it moves as described and rocks over the pivoted connecting member 2'5 and consequently moves the corresponding selector bar Zl from the position shown towards the left. Of course, if the permutation bar isalready in that position, no movement .takes place. If, however, the corresponding permutation frame is in the lower position, then the projection 23 abuts against the upper projection I 3 of the corresponding permutation frame and the lever Zi 2l is rocked counter-clockwise into the position shown at 2| 9 in Figure l.

The gear for tripping the shaft l5 and the detent 3 is controlled from an additional sliding frame 99. There is an additional vane Hi3 below the five vanes 13 and the projections 3 on the frames 1 are'soarranged that when any key lever is depressed, thevane I0!) is tilted, its shaft IUI being rocked slightly counter-clockwise. This causes the additional frame 98 to be thrust down Then through the arm 13, a detent HM is depressed, releasing the stop surface 135 on the shaft iii. The latter is driven and, at a certain point in its revolution, a cam H16 depresses the right hand end of the detent 3 which is pivoted at l3! so that the shaft l is released. In due course, the arm I33 is restored bya cam Hit.

The result therefore on depressing a key lever A is first of all that the five selector bars 2'! 21 are each set either in the position to the right as shown at 21 in the drawings, or in a position more to the left as shown at 21, with the result .that a projecting tail 28 223' of each selector bar either registers with a rear extension 23 of the corresponding selecting lever 33 33 or the tail 23 is moved to the right with the selector bar 2? and leaves the projection 29 free.

As illustrated, the selecting devices consist of five levers 33 33 each pivoted at 3! and each allocated so as to co-act with the corre sponding selecting cam 2 2 There is an additional lever 33 also pivoted at 3! and co operating with the cam 2 for giving the start impulse but not co-operating with any selector bar such as 21 21 When the shaft l starts rotating, the cam 2 co-operates with the corresponding selecting lever 33, the latter is allowed to fall down the step of the cam 2 and thus move towards the centre of the shaft i, being urged in that direction by the pressure of a common pivoted member 32 which has a bar 33 extending over all five of the selecting levers 33 33 and over the lever 33. The common member 32 is pivoted at 34 and tends to be moved counterclockwise by a tension spring 35. As the levers 33 33 are all in their lower positions at this time, the member 32 is rocked by the spring 35 and the bar 33 descends to give the start impulse as will be described below. The cams 2 2 in succession come into the positions which they tend to lift the corresponding levers 33 33 and whether they are able to lift them or not depends on the position of the respective selector bars 21 2Y In Figures 1 and 2, the selector bar 27 is shown displaced to the right with its tail 23 immediately above and therefore in registration with the extension 23 of the lever 33. Thus, when cam 2 comes into position to lift this lever, the right hand end of the latter cannot rise and, therefore, its left hand end is forced up and lifts the common bar 33. The other four levers 30 30 33 and 33 are not restrained at their right hand ends by the tails of their selector bars, so that when their respective cams come into action, their right hand ends are free to rise and these levers do not lift the common bar 33.

A spur wheel 36 is fixed to the shaft l and engages with a small pinion 31 fixed to the transmitting cam shaft 33. The gear ratio is such that the transmitting cam shaft 33 makes three and a half revolutions for each character transmitted, that is, one half a revolution for each code impulse, one half a revolution for start and one half a revolution for stop. The shaft 38 is mounted so as to be slidable in the direction of its axis and carries a cam 39 arranged to operate selectively one or other of a pair of arms 40, 4| of a pivoted contact member 4-2. As can be best seen in Figure 2, the arm 4| is cranked so that the ends of the arms 43, 4! are staggered or displaced relatively to one another in the direction of the axis of the transmitting shaft 38.

As seen in Figure 2, this shaft is moved in the axial direction depending upon the position of the common bar 33. The forward end of the member 32 engages a fork in a bell crank 43 which is pivoted about an axis 44 at right angles to the axis of the shaft 38. Thus, when the selecting cams 2 allow the member 32 to rock slightly counter-clockwise, the forward end of the latter descends and through the bell crank 48 moves the shaft 38 to the left in Figure 2; then the cam 39- presses against the arm M and the member 42 is rocked counter-clockwise and, at its upper end, makes contact between members 45 and 46 which results in sending an impulse of one sign, for example a marking impulse, to the line. As the cams 2 and 2 do not lift the bar 33, the contacts 45, 46 remain closed and two more marking impulses are sent. As, however, the next selector bar 2l prevents the lever 30 from lifting at its right hand end, it lifts the common bar 33 and causes the member 32 to rock clockwise and the member 32 through the bell crank 43 moves the transmitting shaft 38 back to the right until the cam 39 is opposite the arm 4!! and during the following half revolution of the shaft 38, the cam 39 presses on the arm 40 thereby swinging over the member and bringing the contacts A and 41 together so as to transmit to the line an impulse of opposite sign, that is to say, a spacing impulse. Finally, the cam 2 completes a whole revolution and lifts the bar 33 to send the stop impulse. The result is that when a key is depressed, the shaft I makes a complete revolution, the shaft 38 makes three and a half revolutions and the cam 39 during those revolutions makes five code contacts in addition to the start and stop, so that the impulses are sent to the line representing the combination which corresponds to the character whose key has been depressed.

I claim:

1. In a transmitting mechanism for a startstop telegraph ada ted and arranged totransmit in addition to starting and stopping impulses, a plurality of code impulses of equal time periods to constitute each character signal,'the combination of a selecting cam shaft, means for intermittently rotating said selecting cam shaft, a signal transmitting mechanism, a single rotary member operatively connected to actuate said signal transmitting mechanism and connecting gearing between said rotary member and said cam shaft, the ratio of said gearing being such that one revolution of said rotary member ocoupies a time equal to an integral number of the signal impulse periods but not exceeding the time period of all the code impulses of one complete character signal.

2. In a transmitting mechanism for a startstop telegraph, adapted and arranged to transmit in addition to starting and stopping impulses, a plurality of code impulses of equal time periods to constitute each character signal, the combination of a selecting cam shaft, means for intermittently rotating said selecting cam shaft, a signal transmitting mechanism, a single rotary member operatively connected to actuate said signal transmitting mechanism and connecting gearing between said rotary member andsaid cam shaft, the ratio of said gearing being such that said rotary member is rotated by an amount of a half revolution during the time occupied by each permuted code impulse.

3. In a transmitting mechanism for a startstop telegraph adapted and arranged to transmit in addition to starting and stopping impulses, a plurality of code impulses of equal time periods to constitute each character signal, the combination of a selecting cam shaft, means for intermittently rotating said selecting cam shaft, a pivoted signal transmitting lever, marking and spac- 0 ing contacts mounted to co-operate with said transmitting lever during therocking movements thereof, a single rotary member operatively connected to actuate said transmitting lever in accordance with the respective signal impulses to be transmitted and connecting gearing between said rotary member and said cam shaft, the ratio of said gearing being such that one revolution of said rotary member occupies a time equal'to an integral number of the signal impulse periods but not exceeding the time period of all the code impulses of one complete character signal.

4. In a transmitting mechanism for a startstop telegraph adapted and arranged to tran'smit in addition to starting and stopping impulses, a plurality of code impulses of equal time periods to constitute each character signal, the combination of a selecting cam shaft, means for intermittently rotating said cam shaft, marking and spacing contacts, a transmitting cam, shaft mounted for rotation and for movement in the direction of its axis, a pivoted transmitting lever formed with two operating projections relatively spaced in the direction of the axis of said transmitting cam shaft, means for shifting said transmitting cam shaft axially into either of two positions in accordance with the respectivesignal impulses to be transmitted, a transmitting cam fixed to said transmitting cam shaft and located to cooperate respectively with said two operating projections in the two axial positions of said transmitting cam shaft to rock said transmitting lever into cooperation respectively with said mark ng and spacing contacts, and connecting gearing between said two cam shafts, the ratioof said gearing being such that one revolution of said transmitting cam shaft occupies a time equal to an integral number of the signal impulse periods, but not exceeding the time period of all the code impulses of one complete character signal.

5. In a transmitting mechanism, for a start-stop telegraph adapted and arranged to transmit in addition to starting and stopping impulses, a plurality of code impulses of equal time periods to constitute each character signal, the combination of a selecting cam shaft, means for intermittently rotating said selecting cam shaft, marking and spacing contacts, atransmitting cam shaft mounted for rotation and for movement in the direction of its axis, a pivoted transmitting lever formed with two operating projections relatively spaced in the direction of the axis of said transmitting cam shaft, means for shifting said transmitting cam shaft axially into either of two positions in accordance with the respective signal impulses to be transmitted, a transmitting cam fixed to said transmitting cam shaft and located to cooperate respectively with said two operating projections in the two axial positions of said transmitting cam shaft to rock said transmitting lever into cooperation respectively with said marking and spacing contacts, and connecting gearing between said two cam shafts, the ratio of said gearing being such that said transmitting cam shaft is rotated by an amount of half a revolution in the time occupied by each permuted code impulse.

6. In a transmitting mechanism for a startstop telegraph adapted and arranged to transmit in addition to starting and stopping impulses, a plurality of code impulses of equal time periods to constitute each character signal, the combination of a selecting cam shaft, means for intermittently rotating said selecting cam shaft, a transmitting cam shaft mounted for rotation and formovement in the direction of its axis, a pivoted transmitting lever formed with two operating projections relatively spaced in the direction of the axis of said transmitting cam shaft, means for shifting said transmitting cam shaft axially into either of two positions in accordance with the respective signal impulses to be transmitted, a transmitting cam fixed to said transmitting cam shaft and located to cooperate respectively with said two operating projections in the two axial positions of said transmitting cam shaft to rock said transmitting lever into cooperation respectively with said marking and spacing contacts, connecting gearing between said two cam shafts, the ratio of said gearing being such that one revolution of said transmitting cam shaft occupies time equal to an integral number of signal impulse periods, but not exceeding the time period of all the code impulses of one complete character signal, and keyboard controlled mechanism for shifting said transmitting camshaft in the direction of its axis in accordance with the signal impulses constituting each character transmitter.

7. Ina transmitting mechanism for a startstop telegraph adapted and arranged to transmit in addition to starting and stopping impulses, a plurality of code impulses of equal time periods to constitute each character signal, the combination of a'selecting cam shaft, a plurality of cams fixed to said shaft for sending the start and code impulses, means for intermittently rotating said selecting camshaft, marking and spacing contacts, a transmitting cam shaft mounted for rotation and for movement in the direction of its axisinto either of two positionsin accordance with the respective signal impulses" to be transmitted and located to cooperate respectively with two of said operating projections in the two axial positions of said transmitting cam shaft to rock said transmitting leverinto cooperation respectively with said marking and spacing. contacts, a plurality of pivoted selecting levers each in operative relation with one of said plurality of cams, a plurality of permutation bars movable to control respectively the movements of said selecting levers, a keyboard controlled mechanism arranged to effect the movement of said permutation bars, mechanism operable in succession by each of said selecting levers forshifting axially said transmitting cam shaft, a transmitting-cam fixed to said transmitting cam shaft and locatedvto cooperate respectively with said two operating projections in the two axial positions of said transmitting'cam shaft to rock said transmitting lever into cooperation respectively with said marking and spacing contacts, and connecting gearing between said two cam shafts, the ratio of said gearing being such that one revolution of said transmitted cam shaft occupies a time equal to an integral number of the signal impulse periods, but not exceeding the time period of all the code impulses of one complete character signal.

8. In atransmitting mechanism for start-stop telegraph adapted and arranged to transmit in 7 addition to starting and stopping impulses, a plurality of code impulses of equal time periods to constitute each character signal, the combination of a selecting cam shaft, a plurality of cams fixed to said shaft operative in succession for sending the start and code impulses, means for intermittently rotating said selecting cam shaft, a transmitting cam shaft mounted for rotation and for movement in the direction of itsaxis into either of two positions in accordance with the respective signal impulses to be transmitted, a transmitting cam fixed to said transmitting cam shaft, a pivoted transmitting lever formed with two projections located to co-operate with said transmitting cam respectively in the two axial positions of said transmitting cam shaft, a plurality of pivoted selecting levers each in operative relation with one of said plurality of cams, a plurality of permutation bars movable to control respectively the movements of said selecting levers, a keyboard controlled mechanism arranged to effect the movement of said permutation bars, amember common to said selecting levers and in operable relationship therewith, a pivoted bell crank operatively connected with said common member and with said transmitting shaft to shift the latter axially upon movement of said common member and connecting gearing between said two cam shafts, the ratio of said gearing being such that one revolution of said transmitting cam shaft occupies a time equal to an integral number of the signal impulse periods, but not exceeding the time. period of all the code impulses of one complete character signal.

RONALD GEORGE GRIFFITH. 

